The purpose of this study is to achieve approval for the use of carbidopa/levodopa/entacapone in early Parkinson's disease (PD) by demonstrating that when used as initial levodopa therapy in early PD, carbidopa/levodopa/entacapone provides significantly greater symptomatic benefit than immediate release carbidopa/levodopa administered at the same levodopa dosage level of 100 mg three times a day (t.i.d.).

The purpose of this study is to achieve approval for the use of carbidopa/levodopa/entacapone in early Parkinson's disease (PD) by demonstrating that when used as initial levodopa therapy in early PD, carbidopa/levodopa/entacapone provides significantly greater symptomatic benefit than immediate release carbidopa/levodopa administered at the same levodopa dosage level 100 mg t.i.d.

Inclusion Criteria:

• Aged 30 to 80 years, inclusive, at time of Parkinson's disease diagnosis
• Idiopathic Parkinson's disease with at least 2 cardinal signs of disease: resting tremor, bradykinesia or rigidity
• Parkinson's disease impairment warranting treatment with a levodopa formulation according to the investigator's assessment

Exclusion Criteria:

• History, signs or symptoms suggesting the diagnosis of atypical or secondary Parkinsonism due to drugs, metabolic disorders, encephalitis or other neurodegenerative diseases
• History of stereotaxic brain surgery for PD (e.g., pallidotomy, deep brain stimulation, tissue transplant)
• Diagnosis of Parkinson's disease for more than 5 years prior to Screening
• Previous use of levodopa in any formulation, entacapone or tolcapone for more than 30 days or anytime within 4 weeks (28 days) prior to baseline
• Use of a dopamine agonist within 4 weeks (28 days) prior to baseline